A Gwynedd police officer accused of assaulting a handcuffed man said he was "justified" in using incapacitant spray, a court has heard.
PC James Burns, 56, told force investigators Michael Stanley, 28, assaulted him and a colleague when they attended an anti-social incident at Penrhyndeudraeth on 10 April 2016.
He denies common assault and two counts of assault causing actual bodily harm.
He and PC Robin Humphreys, 27, also deny trying to pervert justice.
PC Burns, of Waunfawr in Caernarfon, said he grabbed Mr Stanley by the neck in response to a threat to head butt him.
On Monday, Matthew Curtis, prosecuting, told Caernarfon Crown Court as officers tried to get Mr Stanley into their vehicle, PC Burns grabbed him by the throat.
He said the incident was being recorded by a body camera worn by another officer at the scene and the footage was shown to the jury.
It showed Mr Stanley sitting in the rear of the car before PC Burns opened the door and sprayed him in the face. Mr Curtis said PC Burns then walked to the passenger side and again sprayed Mr Stanley.
Mr Stanley was charged with public disorder, assaulting police and criminal damage - but the case against him was dropped after police body-cam footage was considered, the jury was told.
Both officers are also accused of trying to pervert the course of justice by giving false statements about the incident.
The trial continues.